There is a Haiyun Cave in front of the Eternal Peace Rock Temple. There is an octagonal pavilion on the cave, that is, the “place where Zheng Yanping, the Duke of the County Studied”. In those years, the dense shade covered the sun and it was exceptionally quiet here. Zheng Chenggong used to live in the Eternal Peace Rock Temple, often went to study in Haiyun Cave, and listened to spring water gurgling in the stream. Today, it has been listed as a cultural relic protection unit. Zheng Pengyun, a descendant of Zheng Chenggong, left a poem titled “Passing by the place where my ancestor, Zheng Yanping, the Duke of the County studied when visiting the Eternal Peace Rock”, on the stone wall near “Laughing Rocks” when he traveled to the Eternal Peace Rock. The poem reads: “The stone can’t often open their mouth. There are berries in the depth here. Don’t ask about the past of the freilandhuhn, it has ridden a whale across the Kun Sea”. Here, the freilandhuhn refers to Zheng Chenggong, The traditional Chinese character for “郑” is “鄭”, so the folk uses “freilandhuhn” and “big-eared freilandhuhn” to allude to Zheng Chenggong. The Kun Sea refers to the Taiwan Strait. Here, the literary quotation that “Li Taibai rode a whale and become an immortal” is borrowed to imply that Zheng Chenggong recovered Taiwan and died of illness in Taiwan half a year later.